Simulation studies in the context of Robert Axelrod’s research on iterative prisoner’s dilemma games focus nearly exclusively on the two-player- version of the game. In contrast, this article reports results of a simulation with an iterated N-prisoners’ dilemma where group size N varies between 2 and 30. The simulation investigates the relative performance of conditional cooperative strategies with increasing group size. Results show that some ‘nice’ strategies like ‘tit-for-tat’ are relatively successful and robust even in larger groups and non-nice environments. (...) However, this does not solve the cooperation problem. On the contrary, the relative success of some ‘nice’ conditional cooperative strategies is paralleled by a rapid decline of cooperation in large groups. (shrink)

Coleman’s Foundations devotes much attention to the role of ‘social capital’ in solving problems of cooperation in dilemma situations. In contrast to the human capital approach, however, there is no stringent theory of social capital allowing for the deduction of empirically testable hypotheses from a set of general principles. This article demonstrates by means of various examples that social capital is an important exogenous factor inducing the evolution of cooperation and the stabilization of cooperation in N-person dilemmas. Some preliminary suggestions (...) are made concerning the measurement of social capital and its ‘rate of return’ as a productive factor contributing to the cooperative solution in dilemma situations. (shrink)